Field of the Invention
The present invention relates to a process cartridge and an image-forming apparatus each including an electrophotographic photosensitive member.
Description of the Related Art
A wide variety of investigations have heretofore been performed on an electrophotographic photosensitive member to be mounted on an image-forming apparatus for improving its image quality and durability.
As a method of improving the abrasion resistance (mechanical durability) of the electrophotographic photosensitive member (hereinafter sometimes simply referred to as “photosensitive member”), a method involving using a radical-polymerizable resin in the surface of the photosensitive member to improve the abrasion resistance has been investigated. In addition, a method involving supplying a lubricant to the surface of the photosensitive member to improve the abrasion resistance has been investigated. Meanwhile, when the abrasion resistance is improved, it becomes difficult to clean the surface of the photosensitive member, and hence an image failure, such as a black spot or a black stripe, becomes a problem in some cases. This is considered to be caused by the following situation. It becomes difficult to remove a portion deteriorated by discharge in the surface of the photosensitive member or a toner adhering thereto with a cleaning unit, such as a blade, while shaving off the surface of the photosensitive member.
In U.S. Patent Application Publication No. 2014/186758, there is a description of an image-forming apparatus including an electrophotographic photosensitive member improved in abrasion resistance with a protective layer obtained by polymerizing a monomer having a triarylamine structure, and a monomer having a urethane group and an acrylic group. In addition, in Japanese Patent Application Laid-Open No. 2013-20012, there is a description of an image-forming apparatus in which a cleaning property is improved by supplying a lubricant to the surface of a photosensitive member to form a coating film of the lubricant, and hence image quality stability and abrasion resistance are improved.
An investigation by the present inventors has found that the image-forming apparatus described in each of U.S. Patent Application Publication No. 2014/186758 and Japanese Patent Application Laid-Open No. 2013-20012 has room for improvement in terms of the occurrence of a black spot and a black stripe during its long-term use.